Flashed incorrect BIOS R9 290 - FPS drops since then

Hi all,

 

Here is the description of problem:

During game play, any game, I'll experience a sudden FPS drop that will last for 10~20 seconds, and then it will disappear. The FPS drops will reappear again at a random timing during the game and will continue to occur.

There's no specific trigger to it.

When there's no FPS drops, I experience FPS>60 and sometimes up to 120FPS.

 

This happens only in Crossfire, NO eyefinity and I roughly experienced it since I incorrectly flashed the BIOS of the main GPU to the secondary GPU. This happened last year.

 

The setup:

Two R9 290 Gigabyte OC edition in CrossFire. Although, both are same brand and edition, they did have slightly different parameters and I guess different BIOS

Windows 10 x64 Creators edition - Which seems to also be causing issues with CrossFire and Eyefinity.

 

My Question:

Is there a way to know which is the correct BIOS for my 2nd GPU? Is a serial number or a sticker on the GPU will help to know that?

It could be a different cause, but since I tried all the drivers I could, and since it happened before the 1st major Windows update, I suspect it's the BIOS.

 

The other evidence is that when I disable crossfire, this issue doesn't present itself.

 

 

Thanks!